Governing mechanism for turbines.



I PATENTED JULY 9, 1907. w. L. R. BMMET. GOVERNING MECHANISM FOR TURBI NBS.

APPLICATION FILED DEG. 28,1905.

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.0 n m? W L m s M No.' 8:59 ,286. 'PATBNI'ED JULY 9,1997. V W'.L.R.EMMET.- GOVERNING MECHANISM FOR TURBINBS.

I APPLICATION FILED D30. 28, 1905.

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UNITED STATES PATENT OFFIG WILLIAM L. R. EMMET, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

GOVERNING MI]CI-IAN'ISIMI FOR TURBINES.

Specification of Letters Patent.

Patented July 9, 1907.

Application filed December 28, 1906. Serial No. 293,604.

To'all whom it may concern: 7 r

' Be it known that I,WILLIAM L. R. EMMET, a citizen of the United States, residing at'Schenectady. county of Schenectady, State of New York,-have invented certain new and useful Improvements in Governing Mechanism forTurbines, of which the following is a specification.

The present invention has for its object to provide av governing mechanism for turbines which is simple in construction, requires a minimum amount of space,

is powerful and quick in operation, and is not subject to overtravel.

For a consideration of what I believe to be novel- Fig. 4 is a plan view of the valve chest and valve-- actuating means; Fig. 5 is'a detail view, partially in se'ction, of the hydraulic or other fiuid pressure motor for actuating the cam shaft; Fig. 6 is a plan view of the motor showing the position of its controlling valve and the actuating means therefor; Fig. 7 is a view in quarter section of the cross-header the motor; Fig. 8 is a view in front elevation of" the valve chest and valve-actuating means: Fig. 9 is a diagrammatic view showing the position of the parts when-the speed of the turbinesliaft is normal for a given load; Fig. 10 shows the position of the parts when the speed of the turbine is abnormal; and a nozzle valve is in the-act of closingh Fig. 11 shows the position of the parts when one of the nozzle valves has just closed; Fig. 12 (Sheet 2) is a detail view of the struts for transmitting motion from one of the levers to a valve; Fig. 13 is a detail view showing an arrangement whereby two or more cum shafts may be operated to control separate sols of valves. and Fig. 14 is a detail view showing an accumulator for supplying fluid for actuating the valves in event of failure of the main source.

Referring to Fig. l, i represents the casing of the turbine. and located above it and supporting the gencl'nlor 2 is a stool 3. The upper end of the generator is closed in byn head 4 which is provided with a dome 5 that surrounds the shaft governor and supports the lever for transmitting motion from the speedresponsive device to the controlling valve or regulator of u hydraulic or other motor. Situated at a convenieut point on the turbine casing is a valve chest 6; in

to prevent over-travel the present illustration only one of these chests is crank is connected to the movable element of the motor 9 by means of the adjustable connecting rod 10. A hydraulic motor is illustrated as'one embodiment of -the' invention, and the outer end of the piston rod is provided with a cross-head 11 that is connected to the as will appear more fully.

chest and on the end of the shait is a crank This upper end of the connecting rod 10. This cross-head is arranged to slide up and down in a frame- 12 carried by the lower end of the motor 9, the latter being attached by a bracket to the head 4- of the generator. I Y

. The-lever 13 is connected to the shaft-governor at one end while the outer end is moved up and down as the 4 speed of the turbine changes. This'in turn moves the controlling valve or regulator of the hydraulic or other motor 9, a suitable follow-up device being provided after appear. a

It is important that the valve mechanism shall occupy a minimum amount of space, and also that every part shall be so constructed that it isa duplicate of every other similatpart; and also that it shall be readily accessilile. It is also important to so arrange the passages within the valve chest leading from the valve-seats to the bowls of the nozzles, that they shall be of minimum length, and be free from sharp bonds or turns. This is importantfor two reasons; first, it prevents undue resistance to the passage'of steam-or other elastic fluid, and also it simplifies the making of the castings.

Referring more particularly to Figs. 2' to 4 inclusive, 6 represents the valve casing which is provided with an inlet 14 and a longitudinally extending chamber 15 whi ch supplies fluid to the individual passages 16, each of which is connected to one or more sections of a sectionalized nozzle 17 for converting the pressure of the motive fluid into velocity. It is preferable to have the nozzle orifices closely associated in order that the jet issuing therefrom may be in the forinof a solid column, but my invention is not limited-in all respects to this construction since under certain conditions the nozzles or nozzle sections can be separated by aspace more or less great. The fluid issuing from the nozzles strikes the bucket-s located adjacent thereto which fractions-11y abstract the energy therefrom. Formed on the upper side of the valve chest are two or more lugs 18 which support the transversely extending plate l9.'the latter of the motor, as will herein-Q sob being provided with t'wooi more bearings 20 for the rock-shaft 7,. On the rock-shaft are mounted as many the head 27.

.struction and one that is not liable to be distorted d ue cam projections 22 as there are valves to be operated. These cam projections are so constructed that a relativcly small movement of the cam about its axis causesthe nozzle valve to be fully opened or fully closed. As shown, the werkinglace of the cam i substantially tangential to its hub. The cam and shaft may be integral or separate as desired. Mounted on top of the valve chest and seated in suitable cylindrical openings therein are as many frames 23 as there are valves. Obviously the number of valves and frames can readily be increased or decrcased'to suit the requirements of the particular machine. with two flanges 24 extending at right angles to theaxi s of the valve spindles for securing it to the valve'chest. On referring to Fig. 4, it will be seen that these flanges are set on a diagonal so that the flange on one frame ovcr laps a flange on the other frame. Bymeans of this arrangement I am able to place a maximum number of valves and frames in a minimum space. The upper end of each of the frames is provided with ahead 25 which forms a support for the upright rods 26 that carry Extending to the right of each leg of the valve frame is a bracket 28 and between the brackets and pivotally supported thereby is a valve-actuating lever 29. This lever is forked at its right-l1and end and is provided with a pivot 30. The left-hand end of the lever is provided with an anti-friction roller 3] that engages with and is actuated by the cam 22. These levers comprise two side n'rembe rs which are connected at the left-hand end by a horizontal web or rib, and on the right-hand side of the valve rod by a vcrti cally extending rib. By reason of this construction a very strong lever is provided of minimum size and .weight. Between the horizontal web and the vertical rib is an opening through which the valve rod passes.

From the foregoing it will be seen that each of thevalve frames comprises a baseportion connecting the two uprights and ahead connecting the uprights at the upper end and two laterally extending brackets which support the levers. This furnishes a very rigid conto any cause. The head andbase poftion being formed integrally, the alining oi'the-various parts is a simple matter. The base portion of each frame is provided with shoulders arranged in step-lil e formation which serve to center the frames and also to prevent the escape of motive fluid from the chest. i 5

Each nozzle valve 35 has an open and a closed operating position and also an infinite'number of interme- 'diate throttling positions. It is provided with a seat 36 that is separate froin the valve chest. Each seat is also provided with a guide 37 formed integrally thercwith, suitable openings being provided for the adinis sion of steani'or other fluid. j The valve stem 38 is provided with an enlarged head to receive the valve 35; the latter being provided witha slotwith overhanging walls to permit of its being slipped over the head by a motion transverseto the axis of the rod. The rod extends through a suitable packing located in the base portion of the valve frame, which packing is adjusted by means of a gland nut 39. T he gland nut is provided with anupwardly extending screw-threaded portion to receive an adjusting nut.- and inside of this upwardly extending portion is asecond suitable packin Owing to the inclined snrlaceof each cam connecting the parts Each of the frames is provided and 45 the piston thereof.

of minimum and maximum diameters there will be a throttling action on the part of the nozzle valves as the I anti-friction roller 31 rides up or down the inclined surface or occupies a position thereon intermediate the ends. As shown, the relation of the parts is such that i one, two or more valves may be in throttling positions l fora given position of the cam shaft. From this it will be seen that the valve rod has an upper and a lower packing which effectively prevents the escape of steam at this point. The upper end of the valve rod is provided with a cross-head 40'. The latter may be of cylindrical or other suitable shape. This cross-head is guided in its vertical movement by suitable guides formed on or carried by the head 25 of the valve frame. Situated between the cross-head and the adjustable nut or abutment 4] is a compression spring 42 which at i all times tends to close the nozzle valve and hold it on its seat. This spring should be located outside of the steam space so that its temper will .not be affected by the hot steam in the chest. It is also advantageous to locate it outside of the chest because space is not so valuable at this point and and adjusted. The nut- '11 is provided with forks which partially surround the uprights 26 and is thereby ,prevcnted fronrturning when the adjusting boll -13 is rotated in one direction or the other. In order to transmit motion from the lever to'thc cross-head -10 two struts or compression members 32 are provided which are provided with cup-like seats 33 and 34, Fig. l2.

The struts are located on opposite sides of the valve rod and it is important to make the seats 33 and 34 rclatively deep so as to prevent. thestruts from jumping out of place when the valves operate. 7

In Fig. 3 the arrangement of the several cows 22 therock-shaft 2]. is shown.

viewed from one end the active surlaccs ol' lhc canis'a i-c so disposed that one is slightly bchind the other. liy

reason of this arrangement one nozzle valve will open after the other and close in like order.

7 Referring to Fig. 5, 9 represents the hydraulic molor The piston is connected by the piston-rod 46 with the cross-head ll, the latt r being mounted in suitable guides in tlic depending frame 12. The uppcr'cnd of the c mnccling. rod H) extending to the rock-shaft 7 is al. pivotally connected to the cross-head. Mounted on the side of the hydraulic motor oriat any other suitable point. is a projection 47-wl1ich carries the pivot for the lever 48.

the latter being connected at its free end to the crosshcad ll. and forming part of the follow-up device to prevent ovcrtravel of. the partsas will hereinafter appear. -Tlic hydraulic motor is controlled by a balanced piston valve 49, and fluid under pressure is al mitted to the space between the pistons on tho valv stem by the pipe 50; fluid is exhausted from the \'linder by the pipe 5]. The fluid {or the motor may be' taken from any suitable source, such as thin which supplies lubricant to the bearings. The valve arranged to control two ports extending to npposilc ends of the cylinder. The \al vc should overlap the ports by only a very small am unt so, that the minimum movement of thc shah g v rnor "will cause the opening or closing ol'ihc ports. The valvc is actuated by a rod 52. best shown in Figs. fllo ll. This rod is connected to the floating lever 53L .ind the inner i-nd it is more easily inspected ml It will be seen that when .l (ll) i In 'fluid to the cylinder. With the piston in this posi of the latter is connected by an adjustable connecting rod 54 with the free end of the governor operated lever 13 (Figs. 1, 9, 10 and 11). The right-hand end of the floating lever 53 is attached by an adjustable connecting rod 55 to the lever 48 of the follow-up device. The rod 52 for actuatihg the piston valve 49 is extended beyond the floating lever and through the casing 56 as at 57 to form a guide for the floating lever and attached parts. The arrangement of the levers48 and 53 and connecting rod 55 is such that the piston-valve 49 or other regulator for controlling the motor will be moved to the closed position after the motor piston and also the cam shaft have been moved a certain distance. In other words, this forms a device which anticipates to a certain extent the movements of the shaft governor and by so doing prevents surging of the machine above and below normal speed, which would take place if such a device were omitted. This forms an important feature of the invention.

Referring to the diagrams, Figs. 9 to 1.1 inclusive,

the action of the hydraulic motor and follow-up device will readily be understood. 58 represents the mainwhich responds to changes in the speed of the turbine.

This speed-responsive device actuates the lever 13 that is mounted on the dome 5 of the generator.

Referring to Fig. 9, it will be seen that the piston of the motor is inthe central position and the piston valve 49 is covering both of the ports admitting tion it is locked against movement and one or more of the nozzle valves .35 are open. The parts will remain in the position shown until' there is a change in load on the turbine which causes the speed to change.

In Fig. 10 it is assumed that the speed of the turbine has been increased, the amplitude of movement of the various parts being'somewhat exaggerated in order to illustrate theoperation of the invention more clearly. The movement of the weights on ,the shaft governor has caused the outer end of the lever 13 to be raised The rod which supports the pivot 60 is connected at its lower end to the lever 48, the latter being suitablypivoted at its right-hand end. Since at the instantthe speed changed, the cross-head 11 was stationary and also the pivot for the lever 48 it follows that any upward movement of the rod 54 must be accompanied by the piston valve 49. This upward movement of the piston valve admits fluid to the up per end of'the cylinder and depresses the piston 45.

Depressingthe piston 45 moves the cam shaft 7 in'a clock-wise direction, and one or more of the nozzle valves 35 will close when theanti-friction roller '31 rolls down the inclined portion of the face of the cam. As soon as the piston starts into motion, the cross-.

head 11 also moves and with it the lea hand end'of'the lever 48 of the follow-up device. 7 This movement of the lever causes the rod55. to lower the position of the pivot 60, which in turn causes the floating-lever 53 to depress the piston valve 49 and close the cylinder against the admission of motive fluid and also lock the piston againstmovement. This actioucommonly takes place before the change in steam admission affects the speed of the shaft, or at least before there is any substantial change'in speed. In Fig. 11 the,

nozzle valve is shown as closed and the pilot valve device which is effective for each position of the parts both in opening and closing.

In Fig.'14 is shown an accumulator containing liquid from a'supply pump or other source and air or other gas under an initial-pressure. The object of this accumulator is two-fold,it acts as a cushioning de ,yice between the supply pump or other source and the motors for actuating the cam-carrying shafts, and also as a means for supplying fluid for a limited time in event of the pump or other source breaking down.

Fluid, for operating the motors is supplied by the pipe 66 containing a check-valve 67' to prevent return.

This pipe feeds the secondary pipes67 and 68 con- 'necting with the inlets 500i the motor cylinders, one on each'side oi the turbine.- The tank is directly connected with the supply pipe so that fluid may freely enter and leave it depending upon the relation existing between the source and the initial air pres sure. A pipeis connected to the tank for supply ing ithe necessary air pressure, .The accumulator should be of suflicient capacity to operate the valves .for'a limited time after the source of supply fails.

Tlius far the invention has been illustrated as applied" only to the first-stage nozzle valves of a multistage turbine, but .I may'use the same mechanism for controlling the admission of steam to'the stages of lower pressure, or the passage-of steam from one stage to another, in which case the valve mechanism will be a d-uplicate of that shown except that the valves themselves will be somewhat larger to accommodate the increased volume of motive fluid. I may actuate the stage valves'by the same motor which actuates the admission valves, or a separate motor may be pro- The levers'48 and 53 and vided for the purpose which is under the control of the 7 same speed-responsive devicegwhich controls the admission valves or; under the control of a different one. Where the admission or stage valves are divided into groups the rock-shaits 7 of the groups may becon- .nected by a suitable mechanism so that one motor may be employed for actuating the sets;

7 In Fig. 13 is-sh'own an arrangement suitable for op the connecting rod 62 will extend at right angles to that shown. v

I have shown my invention as applied to a vertical machineof the Curtis type, but it may be used with machines of other types either occupying a vertical or horizontal position. i

In the present embodiment oi the invention, motive fluid flows through the turbine inan -axial direction, but the? invention isapplicable to machines in which the flow is in a radial or other direction.

One important feature of the invention resides in the .i'act that by removing the two bolts passing throtsh the flanges in each'valve irame,'the latter, together with the nozzle valve actuating lever, closing spring, etc., can be removed as a unit, and this without changing the tension on the spring. In this connection it is to be noted that the diameter of the nozzle valv is loss than the diameter of the opening in the va e chest receiving the valve frame. Making the frames.

valves, actuating levers, etc., duplicates greatlysimpliiies the valve mechanismand permits of assembling the parts of each valve on a woric bench or other suitable stand and afterwards mounting the assembled parts on the turbine. In.t.his way the tension of the springs can be correspondingly adjusted. By blocki-ng ll1) ti.l.(ll oi' the levers thecarns and their supporting rock-shaft can be removed as aunit without taking By disposing the levershetween the guides for the valves and the-valves themselves, I am enabledto reduce the vertical height of the parts to a .minimum consistent with the character of the apparatus and the work, to be performed. 7 The cross-heads or guides, being located outside of the steam space, are free from troubles due to excessive heating and may be readily lubricated. By locating the parts outside of the steam spacetheir action can be observed and any defect immediately corrected. The po itions ol the lovers serve to,indieaite the valves that are open, the valves that are closed' and the one that is doing the regulating by opening and closing a comparatively freq .icnt intervals.

In accordance with the provisions of the patent statutes, I have described the principle of operation of myinvention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

' 1. ln u governing mechanism for elastic-fluid turbines.-

lhc combination of a plurality of valves controlllng'the u'dmission of motive fluid to the turbine, levers for actuatinc: the valves, cams for moving jibe levers in a manner to from over-trn veling.

bends and valves in one direction. levers for actuating t'ie valves in opposition to the springs, cams for actuating the valve stems, guides for the stemslocat ed outside of the valve casing. levers for actuating the valves in predetermined order, and a motor responding to speed changes of the turbine for actuating the levers.

In a governing mechanism for elastic-fluid turbines/ the combination of a plurality of valves controlling the admission of motive fluid to the turbine, guides for thevuive stems located outside of the valve casing, levers for uctua-ting the valves in predetermined order to increase or decrease the supply of motive fluid to the turbine. a motor responding to speed changes of the turbine for actuating the levers, and a follow-up device for preventing the motor 4. In a governing mechanism for elastic-fluid turbines, the combination of a plurality of valves controlling the ad mission of motive fluid to the turbine, guides for the valve stems, levers for actuating the valves which are located between them and the guides, and a motor fonac-tuatihg the levers which is responsive to speed changes of the tur' bine.

In a governing, mechanism for elastic-fluid turbines, the combination of a plurality of valves controlling the admission of motive fluid to the turbine, cross-heads for guiding the -valve stems, springs which urge the crossheads and valves in one direction, levers for actuating the valves in opposition to thesprin'gs, cams for actuating the levers, and :1 motor which rocks the cums as the speed of the turbine changes:

6. In H governing mechanism for elastic-fluidturbines, the combination of a plurality of valves controlling the admission of motive fluid to the tiirbine, cross heads for guiding the valve stems. springs which urge the cl'ii hthereon comprising a base portion, a head. a connecting piece between the base and head, and n bracket, a valve stem which extends through the frame, and a lever for actunting the valve stem which is pivotally supported by the bracket. I

8. In a governing mechanism for turbines. the combination of :1 valve chest containing a plurality of valves, frames through which the stems of the valves extend, cross-heads engaging the frames for guiding the valve stems, lovers ior actuating the valves which ar e'located between the cross-heads and the valves. cams for actuating the levers, and a motor for moving; the cams to and fro.

9. in a governing mechanism for turbines, the combinution of a valve chest cmirainin; .1 plurality of valves, frames through which the stems of the valves extend. cross-heads engaging the frames for guiding the valve stems, springs acting on the cross-heads to move the valves in one direciimi, levers for actuating the valves, cams for moving the lovers successively. motor for moving-the cums lo and fro us the speed of the turbine changes. and u reculutor for the motor responsivr to speed changes.

10. in a governing mechanism lor turbines. the combi nation of a valve chest ontaininz: a plurality of valves. dupllcaie frames for the valve-actuating mechanism which are closely associated, :1 Valve-actuating lc"cr pivoted to ouch frame. cums ouu shaft exteinhnghl' right: angles to the levers. the said cums having :1 to und-fro movement. and u motor responsive to speed changes t'orimparliiu: movement to the cums, the amount and direction ol said movement hearing a definite I'elation to the changes in load.

il. in a governing mechanism for turbines. the combination oi a valve chest contninimr a plurality of valves, duplicate frames for the valve-actuating mechanism which are closely associated, a valve-actuating: lever pivoted to each frame, cams on a shaft extending at right angles to the levers, the.said cams having to-und-fro movements. :1 support for the cams that is sccurcd to the valve chest, and a motor responsive to spccd changes for imparting movement to the cams, the amount and direction of said movement bearing a definite relation to the changes in load.

12. In a governing mechanism for turbines, the combination of a valve chest containing aplurality of valves, means including levers for directly opening and closing the valves, cams which have a to-and-fro motion for actuating the valves through the levers and causing some of them to be normally opened and others normally closed, a motor for moving the cams, a regulatorfor the motor which responds to movements of a speed governor, and a followup device which anticipates the changes in speed of the turbine and prevents the motor from overtraveling.

13. In a governing mechanism for turbines, the combination of a valve chest containing a plurality of valves, cross-heads for guiding the outer ends of the valve stems, springs locatedoutside of the chest for moving the valves in one direction, levers also located outside of the chest for moving the valves in the opposite direction, a fluid-actuated motor acting throughthe springs and levers to open and close the valves, and a regulator for the motor sensitive to speed variations of the turbine.

14; In a governing mechanism for turbines, the combination of a valve chest containing a plurality of valves, cross-heads for guiding the outer ends of the valve stems, springs located outside of the chest for moving the valves in one direction, levers also located outside of the chest for moving the valves in the opposite direction, cams for operating the levers successively to increase or decrease the supply of motive fluid to the turbine, a fluid-actuated motor for rocking the cams as the demand for motive fluid changes, a regulator for the motor responsive to speed changes, and a followup device to prevent overtravel of the motor.

15. In a governing mechanism for turbines, the combination of a plurality of valves located within a valve chest which vary the admission of motive fluid to the turbine, cross-heads for guiding the stems of the valves, levers for actuating the valves, a fluid-actuated motor for moving the levers and a regulator responsive to speed variations of the turbine for regulating the motor.

16. In a governing mechanism for turbines, the combination of a plurality of valves located within a valve chest which vary the admission of motive fluid to the turbine, cross-heads secured to and guiding the valve stems, levers for actuating the valves, means intermediate the cross heads and the levers for transmitting motion from one to the other, and cams which have a rocking motion for moving the valves and are themselves responsive .to speed variation.

17. In a governing mechanism for turbines, the combination of valves located within a valve chest which vary the admission of motive fluid to the turbine, bifurcated levers for actuating the valves, stems for the valves which extend freely through the'levers, means for transmitting motion from the levers to the valves, a rocking cam for actuating each of the levers, and a means responsive to speed changes for moving the cams.

18. In a governing mechanism for turbines, the combi-' nation of valves located within a valve chest which vary the admission of motive fluid to the turbine, a frame for the actuating mechanism of each valve, a lever pivoted to the frame for moving the valve, :1 spring tending to oppose the action of the lever 'on the valve, an adjustable abutment for the spring'supported by the frame, and speed-responsive means for operating the levers.

19. In a governing mechanism for turbines, the combination of valves located within a valve chest which vary the admission of motive fluid to the turbine, levers for actuating the valves, a cam having a to-and-fro movement for operating each of the levers, a motor for moving the cams as the load conditions on the turbine change, and a follow-up device for preventing overtravel of the motor which includes a floating lever, and a member connecting 'the lever with the motor.

20. In a. governing mechanism for turbines, the combination of valves located within a valve chest which vary the admission of motive fluid to the turbine. levers for directly actuating the valves. a single motor for actuating the valves successively through the levers to increase or decrease the supply 01' motive fluid delivered to the tinblue, a regulator for the motor which is connected to a speed governor, a floating lever included in the connection between the governor and the regulator, and a connection between the floating lever and the motor which moves the regulator to its initial position after one or more valves have been opened or closed.

21. in a governing mechanism for turbines, the combination of'vulves arranged in sets for governing the passage of motive fluid through a turbine, levers for actuating each set of valves. rains for moving the levers. a motor which is common to the cams. and a regulator for the motor which is responsive to speed variations.

22. In a governing mechanism for turbines, the combination of valves arranged in sets for governing the passage of motive fluid through a turbine, levers for actuating each set of valves, cams for moving the levers, a connection between the cams for transmitting motion from one to the other, a motor common to the cams for moving themra regulator for the motor, and a means for preventing overtravel of the motor.

23. In a governing mechanism, the combination of a regulating valve, :1 fluid-actuated motor for opening and closing it, a load-responsive device governing the motor, a source of fluid supply for the motor, and an accumulator in circuit between said source and the motor.

24. In a governing mechanism, the combination of a plurality of .valves, a fluid-actuated means for successively operating the valves, a source of fluid supply, an accumulator containing a body of compressed gas and included in circuit between the source of supply and the actuating means, a means for maintaining the accumulator. under suitable pressure, and a speed-responsive device controlling the movements of the valve-actuating means.

25. In a governing mechanism for turbines, the combination of a valve chest having an inlet and containing a chamber and a plurality of independent passages leading from the chamber, nozzles supplied by the passages, valves for controlling the flow of fluid from the chamber to the passages, the stems of which extend through the chest, levers for actuating the valves pivotally supported at one side of the valve stems, a camfor actuating each of the levers mounted on the other side of the stems, a fluid actuated motor responsive to load changes for turning the cams, and a means for preventing the motor from over-traveling.

. 26. In a governing mechanism for turbines, the combination of a valve chest, a plurality of valves therein, independent frnmes supporting the valve actuating mechanism, a pivoted lever for each valve supported by the frames, a cam for actuating each lever, a shaft common to the cams, the pivots for the levers being located on one side of the valve stems and the cams on the other, and a support detachably secured to the chest and carrying the camshaft so that the shaft and cams can be assembled in place or removed without disturbing the valves, levers and frames, and vice versa.

27. In a governing mechanism, the combination of a chest. a valve therein having a stem projecting through a wall of the chest, a lever for actuating the valve, a cam for moving the valve in one direction, a spring for moving it in the other. and compression members located on opposite sides of the stem for transmitting motion between the 

